Construction of alumina framework with a sponge template toward highly thermally conductive epoxy composites

Abstract Ceramic‐based polymer composites are commonly utilized as thermal management materials due to their high thermal conductivity and electrical insulation properties. One efficient method to enhance the thermal conductivity of these composites is by constructing a three‐dimensional thermal conductive network within the polymer matrix. In this study, alumina was coated onto the surface of polyurethane (PU) foam, followed by high‐temperature removal of the PU foam and sintering of the alumina sheets to obtain a continuous alumina framework. Epoxy resin was then infiltrated into this alumina framework to fabricate highly thermally conductive EP/f‐Al 2 O 3 composites. The EP/f‐Al 2 O 3 composite achieved a thermal conductivity of 2.44 W m −1 K −1 when the filler content of 26.8 vol%, representing a 400% improvement compared to EP/Al 2 O 3 composite with randomly dispersed fillers, and a remarkable 1180% enhancement compared to epoxy resin. Infrared thermal imaging also confirmed the excellent heat dissipation capability of the EP/f‐Al 2 O 3 composites. Overall, this research presents an effective method for producing highly thermally conductive and electrically insulating composites that can be used in electronic thermal management applications. Highlights Fabrication of porous Al 2 O 3 frameworks/epoxy composites. Porous Al 2 O 3 frameworks were fabricated by polyurethane foam template. The obtained EP/f‐Al 2 O 3 composite exhibited excellent thermal conductivity.